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Constellation X-ray Mission


1,500 sq cm at 40 keV. Energy resolution 1 keV. 30-60 arc sec HPD angular resolution ... evolution of black hole properties by determining spin and mass ... – PowerPoint PPT presentation

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Title: Constellation X-ray Mission

Constellation X-ray Mission
Constellation-X Mission Overview
  • Use X-ray spectroscopy to observe
  • Black holes strong gravity evolution
  • Dark Matter throughout the Universe
  • Production and recycling of the elements
  • Mission parameters
  • Telescope area 3 m2 at 1 keV
  • 25-100 times XMM/Chandra for high resolution
  • Spectral resolving power 300-3,000
  • 5 times better than Astro-E2 at 6 keV
  • Band pass 0.25 to 40 keV
  • 100 times RXTE sensitivity at 40 keV

Enable high resolution spectroscopy of faint
X-ray source populations
X-ray Spectroscopy Comes of Age
Chandra Log N - Log S
The current threshold for finding X-ray selected
AGN exceeds the spectroscopic capability of
optical telescopes to identify the host galaxy
(33 objects at I gt 24) High resolution (Rgt300)
spectrometers on Chandra, XMM-Newton and Astro-E2
typically reach fluxes where the sky density is
0.1 to 1 sources per sq degree
X-ray imaging has outstripped both optical and
X-ray spectroscopy! Constellation-X will
increase by a factor 1000 the number of sources
available for high resolution spectroscopy
Constellation-X will obtain high resolution
spectra of the faint X-ray sources to determine
redshift and source conditions
Constellation-X Mission Performance
Two coaligned telescope systems cover the 0.25 to
40 keV band
  • SXT Spectroscopy X-ray Telescope
  • 0.25 to 10 keV
  • Effective area
  • 15,000 sq cm at 1 keV
  • 6,000 sq cm at 6 keV
  • Resolution 300-3000 with combination of
  • 2eV microcalorimeter array
  • reflection grating/CCD
  • 5-15 arc sec HPD angular resolution
  • 5 arc sec pixels, 2.5 arc min FOV
  • HXT Hard X-ray Telescope
  • 10 to 60 keV
  • 1,500 sq cm at 40 keV
  • Energy resolution lt 1 keV
  • 30-60 arc sec HPD angular resolution

Plasma Diagnostics with Constellation-X
The Constellation-X energy band contains the
K-line transitions of 25 elements allowing
simultaneous direct abundance determinations
using line-to-continuum ratios
The spectral resolution of Constellation-X is
tuned to study the He-like density sensitive
transitions of Carbon through Zinc
Black Holes and Strong Gravity
  • Constellation-X will probe close to the event
    horizon with 100 times better sensitivity than
  • Observe iron profile from close to the event
    horizon where strong gravity effects of General
    Relativity are seen
  • Investigate evolution of black hole properties by
    determining spin and mass over a wide range of
    luminosity and redshift

Simulated images of the region close to the
event horizon illustrate the wavefront of a flare
erupting above material spiralling into the black
hole. The two spectra (1000 seconds apart) show
substantial distortions due to GR effects.
Black Hole Evolution
Chandra deep field has revealed what may be some
of the most distant objects ever observed
Sources making up the X-ray background
The earliest galaxies
The first black holes
Constellation-X will obtain high resolution
spectra of these faintest X-ray sources to
determine redshift and source conditions
Hidden Black Holes
Many black holes may be hidden behind an inner
torus or thick disk of material
Only visible above 10 keV where current missions
have poor sensitivity
Cosmology with Clusters of Galaxies
Precision spectroscopy by Constellation-X of
faintest, most distant clusters will determine
redshift and cluster mass and the evolution of
their parameters with redshift
The Missing Hydrogen Mystery
  • An inventory of the visible matter in todays
    Universe gives only 20 of the baryons (mostly
    Hydrogen) found at high redshift in the
    Lyman-alpha forest
  • Models for the formation of structure under the
    gravitational pull of dark matter predict the
    "unseen baryons are in a 0.1 to 1 million degree
    K intergalactic gas

HST revealed 15 of these predicted baryons
using UV OVI absorption lines seen against
bright background Quasars - most sensitive to
0.1 million degree gas
Constellation-X will search for the remainder and
can detect up to 70 using O VII and O VIII
absorption lines - most sensitive to 1 million
degree gas
Together, UV and X-ray observations constrain the
Galactic Halos
The composition and state of the tenuous hot
halos of Galaxies can be accurately measured via
K or L shell absorption of X-rays against
background quasars
There are more than 300 bright X-ray galaxies for
which such measurements can be made
Spectra of two typical quasars absorbed through
two different hydrogen column densities in the ISM
Constellation-X Mission Concept
  • A multiple satellite approach
  • A constellation of multiple identical satellites
  • Each satellite carries a portion of the total
    effective area
  • Design reduces risk from any unexpected failure
  • Deep space (L2) orbit allows
  • High observing efficiency
  • Simultaneous viewing

  • Reference configuration
  • Four satellites, launched two at a time on Atlas
    V class vehicle
  • Fixed optical bench provides a focal length of 10
  • Modular design allows
  • Parallel development and integration of telescope
    module and spacecraft bus
  • Low cost standard bus architecture and components

Reference Design
Spacecraft Bus
Spacecraft Bus
Telescope Module
High Gain Antenna
1.6 m Diameter Spectroscopy X-ray Telescope
Mirror and Gratings
Solar Panel
Hard X-ray Telescope Mirrors (3)
Optical Bench (enclosure removed for clarity)
Hard X-ray Telescope Detectors (3)
CCD Array
Cooler with X-ray Calorimeter
SXT Design
SXT Segmented X-ray Mirrors
  • Requirement Highly nested reflectors with 1.6 m
    outer diameter, low mass and overall angular
    resolution of 5-15 arc sec (HPD)
  • Segmented technology meets mass requirement
  • Requires 10 times improvement in resolution and 4
    times increase in diameter compared to Astro-E2
  • Now the mission baseline - shell mandrels larger
    than 0.7m are not available, plus good progress
    made with demonstrating feasibility of segmented
  • Recent Progress
  • Demonstrated required performance at component
    level, necessary to begin system level testing
  • Successfully replicated glass segments from 0.5 m
    precision Wolter Mandrel with performance limited
    by forming mandrel
  • Initiated Engineering Unit design
  • Initiated procurement for 1.6 m diameter segment
  • Partners GSFC, MIT, SAO, MSFC

SXT Engineering Unit
  • Goal is to approach Con-X resolution requirement
    in unit incorporating all aspects of SXT flight
  • Precisely formed segments
  • Etched Si alignment bars
  • Flight assembly and metrology approach
  • EU is flight-like size (inner module)
  • Utilizes existing Zeiss metal mandrels
  • (50 cm dia. 8.4 m f.l. 5 surface)
  • Phased build up, with increasing complexity
  • Units will be tested in X-rays and subjected to
    environmental testing
  • Delivery mid-2003

Precision Actuators
X-ray Calorimeters
  • Requirement 2 eV FWHM energy resolution from 1
    to 6 keV at 1000 counts/s/pixel in 32 x 32 pixel
  • Parallel Approach Transition Edge Sensor (TES)
    and NTD/Ge Calorimeters
  • Progress
  • Demonstrated 2 eV resolution at 1.5 keV and 4 eV
    at 6 keV using TES approach on demonstration
  • Achieved adequate thermal isolation and 2.5 eV
    resolution at 1.5 keV using a flight sized TES
  • Quantified TES detector noise to enable energy
    resolution budget
  • Fabricated 2 ? 2 TES array for initial cross talk
  • Demonstrated a new imaging TES approach that will
    potentially enable increase in field of view
  • Achieved 4.8 eV resolution over full range (1-6
    keV) with NTD/GE detector
  • Partners GSFC, NIST, SAO, UW, LLNL, Stanford

3 mm
2.5 eV (FWHM) _at_1.5 keV
Constellation-X Hard X-ray Telescope
  • Requirement Maximum energy gt 40 keV, effective
    area gt 1500 cm2, angular resolution lt 1 arc min
    HPD, FOV 8 arc min, energy resolution lt 10
  • Approach Depth-graded multilayer grazing
    incidence optics (shell or segmented) and CdZnTe
    pixel detectors
  • Progress
  • Successful balloon flights (HERO and Infocus) in
    2001 demonstrated first focused hard X-ray images
  • Improved CdZnTe detector performance
  • Energy resolution 390 eV (at 18 keV) and 550 eV
    (at 60 keV)
  • Threshold (theoretical) is 2 keV 8 keV
  • Demonstrated sputter coating on interior of
    cylindrical shells
  • Evaluated formed glass prototype optic with 5
    coated surfaces
  • lt 60 arc sec HPD and good reflectance at 60 keV
    (single bounce)
  • Partners Caltech, GSFC, Columbia U., MSFC,
  • Harvard, SAO, NU, NRL

Reflection Grating Spectrometer
In-plane Mount
Radial Groove Gratings
Potential for Greatly Improved Performance
Primary Response
lt35 Response
Extended CCD
ASSUMPTIONS 5500g/mm 15 SXT 2 gratings 2
Calorimeter 2eV
Mission Goal
I-P n1
Mission Requirement
I-P n2
Figure of Merit
area x resolution 106
Energy (keV)
Top Level Schedule (In-guide FY07 New Start)
  • Constellation-X emphasizes high throughput, high
    spectral resolution observations the next major
    objective in X-ray astronomy
  • A High Priority Facility in the influential
    McKee-Taylor Decadal Survey
  • Mission design is robust and low risk
  • Assembly line production and multi-satellite
    concept reduces risk
  • First launch in 2010 timeframe
  • Facilitates ongoing science-driven,
    technology-enabled extensions
  • Substantial technical progress achieved
  • Replicated segmented reflector performance at
    component level
  • Calorimeter single pixel spectral resolution
  • Hard X-ray telescope optics and detector
  • Ramping up flight scale technology development
  • On track to demonstrate critical milestones by